#1  
Old 07-31-2019, 10:38 AM
MescaBug's Avatar
MescaBug MescaBug is offline
Ultimate Warrior
 
Join Date: Sep 2008
Location: Montreal, Quebec, Canada
Posts: 1,634
Default Cracked exhaust manifold flange - Weld or??

While priming, I noticed we cracked the exhaust flanges when installing the new studs. Stock rebuild, 72' 400 with mild cam. Nothing exotic, I drive this car an average 2000 miles per year.

Can I use as is? Or should I weld? Pretty sure they will hold, but need opinions. I was ready to paint and install tomorrow, welding would hold me back for a few days...




  #2  
Old 07-31-2019, 10:56 AM
leeklm's Avatar
leeklm leeklm is offline
Ultimate Warrior
 
Join Date: Mar 2013
Location: Mpls, MN
Posts: 1,747
Default

There can be a fair amount of stress on the flanges as your engine will rock/flex against the exhaust system. I would definitely have the flanges repaired. In the past I have had decent results brazing cast iron manifolds.

Sent from my SM-G965U using Tapatalk

__________________
68 Firebird-- Street/Strip - 400/461 Eagle Forged Bottom End & Ross Flat top pistons. KRE 325 CFM D port, Ultradyne 263/271 @.050, .4267 lift. Crower Solid roller lifters and 1.65 stainless rockers. Quickfuel 1000 on Torker2 intake and 2" open spacer. Hedman 1.75" headers. TH400 w/brake. Ford 9" w/3.80 gears & 28x9 Hoosier pro bracket drag radial. Best ET: 1.35 60ft, 6.29 @ 107.20 mph, 9.99 @132.33 mph. 3,300 race weight
  #3  
Old 07-31-2019, 11:20 AM
GT182's Avatar
GT182 GT182 is offline
Ultimate Warrior
 
Join Date: Aug 2007
Location: New Castle, Delaware - Member of POFC
Posts: 8,833
Default

Don't run with the cracks... repair them. Or, put on new exhaust manifold(s).

__________________


Gary
Get in, ShuT Up, Hang On!
Member of the Baltimore Built Brotherhood
MY GTO built 4th Week of March 1966
"Crusin' Is Not A Crime"
Keep yer stick on the ice.
  #4  
Old 07-31-2019, 09:43 PM
MescaBug's Avatar
MescaBug MescaBug is offline
Ultimate Warrior
 
Join Date: Sep 2008
Location: Montreal, Quebec, Canada
Posts: 1,634
Default

I'll get them fixed. I hate setbacks. You know how it is..

But, better be safe than sorry.

  #5  
Old 07-31-2019, 10:51 PM
pfilean's Avatar
pfilean pfilean is offline
Ultimate Warrior
 
Join Date: May 2007
Location: West Des Moines, IA
Posts: 1,932
Default

Repair can be done. Use a high nickel weld filler. Grind out the crack. Get the manifold to 600-800 degrees and keep hot while welding. When welding is done embed in vermiculite and let it slow cool.

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:17 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017